Ground electrode and test circuit

ABSTRACT

An electrical-surgical machine using high-frequency currents connected to an active electrode and a patient ground plate electrode. The ground plate electrode is a one-piece disposable flexible sheet member having an electrical conductive skin releasably attached to a clamp connected to a line leading to the electrical-surgical machine. A circuit-testing unit checks the entire circuit, including the electrical connection between the patient and ground plate electrode, as well as the electrical connection between the clamp and the ground plate. The releasable clamp has a pair of spaced flat electrical contacts in surface engagement with the electrical conductive skin of the ground electrode. One form of the clamp has a pair of plate contacts attached to and pivotally mounted on flat electrically insulative covers.

O United States Patent [151 3,642,008

Bolduc 1 Feb. 15, 1972 [54] GROUND ELECTRODE AND TEST 1,498,059 6/1924Tyler 1 28/416 CIRCUIT 1,967,815 7/1934 Frieberg 174/89 2,827,056 3/1958Degelman 128/422 [72] Inventor: Lee R. Bolduc, Minneapolis, Minn. [73]Assignee: Medical Plastics, Inc., Minneapolis, Minn. FOREIGN PATENTS ORAPPLICATIONS [22] Filed: Oct 15 1969 1,139,927 11/1962 Germany..l28/303.13 [21] Appl. No.: 866,630 Primary Examiner-Richard A. GaudetAssistant Examiner.l. B. Mitchell Related Apphcatlon Dam Attorney-Bard,Braddock & Bartz [63] Continuation-impart of Ser. No. 762,582, Sept. 25,

1963 [57] ABSTRACT An electrical-surgical machine using high-frequencycurrents [52] US. Cl ..l28/4l6, 128/3031, 324/62 connected to an actiwelectrode and a patient ground plate lnt. G01! electrode' The groundplate electrode is a one piece p [58] Field of zeal-ch Z g ble flexiblesheet member having an electrical conductive skin 128/4 41 32 I5 4releasably attached to a clamp connected to a line leading to l 2 theelectrical-surgical machine. A circuit-testing unit checks 56 R f Ctedthe entire circuit, including the electrical connection between 1 eerences I the patient and ground plate electrode, as well as theelectrical UNITED STATES PATENTS connection between the clamp and theground plate. The releasable clamp has a pair of spaced flat electricalcontacts in 2,465,722 3/ 1949 Hamtlton.. ..339/255 P surface engagementwith the electrical conductive skin of the 3,031,642 4/ 1962 Gattner......339/255 P round electrode. One form of the clamp has a pair of plate2,547,041 4/1951 Piar ....128/303-1 contacts attached to and pivotallymounted on flat electrically 2,012,316 8/1935 Miles ..174/ 177insulative covers, 3,144,019 8/1964 Haber.... ....128/2.06 A 3,135,2646/1964 Tischler et al ..l28/419 P 23 Claims, 19 Drawing Figures GROUNDELECTRODE AND TEST CIRCUIT CROSS REFERENCE TO RELATED APPLICATION Thisapplication is a continuation-in-part of U.S. Pat. application Ser. No.762,582 filed Sept. 25, I968.

BACKGROUND OF INVENTION In 1907, Pozzi demonstrated fulguration as acure for malignant disease to the Paris Academy of Medicine, using anOudin resonator and unipolar current of a frequency around half amillion cycles per second. I-Iis results were by no means uniform, andit was left to Iredell and Turner, in 1919, to

demonstrate true diathermy by providing a plate, 6 by 12 inches, for thereturn circuit. They showed that the effects of the treatment wereentirely due to heat destruction of tissues and were first to use awater pipe to ground both the indifferent electrode and the patient.This contribution to safety has remained until the present day. In use,heat is developed at both the active electrode and the indifferent orground electrode, commonly a lead plate, in surface contact with theskin of a patient. The heat generated is inversely proportional to thesquare area of these electrodes. The ground electrode must be of acertain size and has to make uniform contact all over its surface sothat the heat is diffused over a. wide area. If the ground electrode haspoint contacts, the patient can be severely burned. In some instances,two ground electrodes are used at the same time to insure adequategrounding of the patient.

Efficient functioning and safety of electrical-surgical machines dependsupon an unimpaired return of current via the indifferent groundelectrode and its cable. If this fails, then the current will choose thenext best route, which will mean a short circuit to ground with aconsequent risk of a diathermy burn. Some machines are equipped with aground test stud that requires the operating staff, before eachoperation, to

check the circuit. This system only monitors the continuity of the cableand its attachment to the ground electrode. It does not monitor theelectrical contact and conductivity between the ground electrode and thepatient.

Various materials are used for the ground plate electrodes. The materialshould be a good conductor and easily malleable. Lead plates have beenthe most practical to use. Some plates have been made of stainlesssteel, zinc and tin, as suggested by Ruben, U.S. Pat. No. 1,973,911, andWappler, U.S. Pat. No 1,662,446.

Copending U.S. Pat. application, Ser. No. 71 1,949, now U.S. Pat. No.3,543,760 describes a disposable ground plate electrode and clamp usablewith an electrical-surgical unit for cautery, fulguration,electrocoagulation, and like surgical procedures. This ground plateelectrode has a continuous electrical conductive aluminum skin securedto an insulated base. The clamp has a substantially flat surface adaptedto be positioned in surface engagement with the aluminum skin to insurean effective electrical connection between the clamp and the electricalconductive skin of the ground plate. This ground plate electrode cannotbe used to check the electrical conductivity between the electrode andthe skin of the patient.

SUMMARY OF INVENTION The invention relates to an electrical continuitytesting circuit to test the electrical connections between a clamp and aground plate electrode and electrical conductivity between the groundplate electrode and the patient, as well as the circuit of a cableattached to the clamp. The ground plate electrode is a disposable sheetmember having an electrical conductive skin which can be separated intwo sections. The clamp has a pair of spaced electrical contact memberswith flat surfaces clamped into surface engagement with the separatesections of the ground plate electrode. One form of the clamp has covermembers which support and insulate the electrical plate contacts. Thetest circuit uses low-voltage power and an indicator to check theelectrical contact between the clamp and ground plate electrode and thecontinuity of the cable between the clamp and electrical-surgicalmachine. One form of the test circuit uses a split ground plateelectrode with a bipolar clamp in a circuit test loop, including abattery and meter to check the electrical resistivity between thepatient and ground plate electrode. In another form of the test circuit,the circuit includes a control operative in response to a completed testcircuit to automatically connect the ground plate electrode to ahigh-voltage circuit.

IN THE DRAWINGS FIG. I is a diagrammatic view of the electrical-surgicalunit equipped with the ground plate electrode and connector of theinvention used on a patient lying on an operating table;

FIG. 2 is a perspective view of the releasable connector attached to anedge of the ground plate electrode;

FIG. 3 is a side view of one form of the connector of FIG. 2, partlysectioned, in assembled relation with a ground I plate electrode;

FIG. 4 is an electrical diagram of a test and control circuit, bipolarclamp, and ground plate electrode;

FIG. 5 is a plan view, with parts broken away, of another form of theconnector;

FIG. 6 is an enlarged sectional view taken along the line 6 6 of FIG. 5;

FIG. 7 is a diagrammatic view of an electrical-surgical unit having asplit ground plate electrode attached to a bipolar clamp connected to acircuit testing unit;

FIG. 8 is an enlarged sectional view taken along the line 8- 8 of FIG.7;

FIG. 9 is an enlarged sectional view taken along the line 9- 9 of FIG.7;

FIG. 10 is a side view, partly sectioned, of the bipolar clamp of FIG.7;

FIG. 11 is an enlarged plan view of the circuit testing unit and cablemale connector;

FIG. 12 is an electrical diagram of the testing circuit, bipolar clampand split ground plate electrode of FIG. 7;

FIG. 13 is a plan view of a split ground plate electrode having a clamplocator hole with parts broken away;

FIG. 14 is a plan view of a bipolar clamp attached to a split groundplate electrode;

FIG. 15 is a side view of the clamp;

FIG. 16 is an enlarged sectional view taken alongthe line I6I6 ofFIG.15;

FIG. 17 is an enlarged sectional view taken along the line 17-17 ofFIG.14;

FIG. 18 is an enlarged sectional view taken along the line l8--l8 ofFIG. 14; and

FIG. 19 is a sectional view similar to FIG. 17 showing a modification ofthe clamp.

Referring to the drawings, there is shown in FIG. 1 anelectrical-surgical unit, indicated generally at 10, illustrated in anoperating environment theater on apatient 11 lying on a table 12. Table12 is supported on floor 13 by an upright base 14 to locate the patientin a convenient position for surgeon 16.

The electrical-surgical unit 10 uses high-frequency current from aportable transformer l7 connected to power supply lines 18 and to anactive electrode 19 by a cable or line 20. The circuit through thepatient I1 is completed with a ground plate electrode 21 located incontact with an area of the skin of the patient. A line or cable 22 isconnected to the electrode 2I through a releasable connector or clamp,indicated generally at 23. Connector 23 is clamped to the ground plateelectrode 21 to complete the electric circuit to the transformer 17. Theopposite end of line 22 is connected to a test and control circuit,indicated generally at 24, carried by the transformer 17. In use, thesurgeon 16, prior to operative use of the active electrode 19, willvisually observe a light '63 on the test and control circuit to see ifthe releasable connector 23 is in electrical contact with the groundplate electrode 21 and determine if high voltage is present in theoperating circuit.

Referring to FIGS. 2 and 4, there is shown the disposable ground plateelectrode 21 ashaving a flat base 26 covered with an electricallyconductive skin27. Plate 21 has an end flange or flap 28 folded overforming a stop edge 29. The base can be impregnated with a plasticmaterial which bonds the skin 27 to the top of the base. The skin is anelectrically conductive material, as sheet metal or aluminum foil. Theground plate electrode 21 is described in detail in copending US.application Ser. No. 711,949, filed Mar. 11, 1968, now US. Pat. No.3,543,760.

The releasable connector 23 functions to provide an electricalconnection between the cable 22 and the ground plate electrode 21.Connector 23, shown in FIGS. 2 and 4, has a C- clamp 31 pivotallycarrying a pair of angularly disposed levers 32 and 33. Asshown in FIG.2, lever 32 has separated contact plates 34 and 36 and rearwardlydirected conductor arms 34A and 36A separated with plastic or othernonelectrically conductive material 37. Lever 33 may have similarseparated plates formed with a rearwardly directed lip 38A to hold thecontact plates 34 and 36 in flat surface engagement with theelectrically conductive skin 27 of the ground plate electrode 21.

Referring to FIG. 3, there is shown a modified conductor 23A having aplate 36A carrying a downwardly directed projection or finger 39extended through a hole 41 in plate electrode 21 and hole 42 in the lip38A. The other contact plate 34 may also have a similar projection orfinger located in aligned holes in plate electrode 21 and the separatedbottom lip. The center of the clamp between plates 34 and 36 can be madewith a projection adapted to pass through a center hole in the groundplate. The projections positively lock the releasable connector 23A tothe ground plate electrode 21 so that it cannot be accidentally removedor partially separated from the plate electrode 21.

The entire connectors 23 and 23A and exposed portions of the levers 32,32A and 33, 33A are coated with a plastic insulative material so thatthe connectors cannot short out the ground plate electrode 21 causingburning of the patient. The lines 43 and 44 from the cable 22 areconnected to the terminal portions of the conductors 34A and 36A,respectively, as shown in FIG. 2.

Referring to FIG. 4, there is shown connector 23 in assembled relationwith the ground plate electrode 21 along with the test and controlcircuit 24. The transformer 17 provides the circuit 24 with alow-voltage source 46 and a high-voltage source 47. Line 48 connects acoil 49 of a relay 51 to the lowvoltage source 46. The coil 49 isconnected to line 43 leading to the conductor arm 34A. A manuallyoperated control switch 52 interposed in the line 48 between the coil 49and the low-voltage source 46 controls the circuit for the low testvoltage and the circuit for the high voltage. The low-voltage circuit iscompleted with a line 53 connected to the line 44 leading to theopposite conductor arm 36A of the connector 23. Relay 51 has threecontacts 54, 55, and 56, and a pair of movable switching elements 57-and58 operably associated with the coil 49. Switching element 57 isconnected with a line 59 to the line 43. Switching element 58 isconnected with a line 61 to the line 44. The contact 54 is connected toa line 62 which leads to the low-voltage line 48. A light 63 isinterposed in the line 62 to indicate an improper or insulatedelectrical connection between the connector 23 and ground electrode 21.The light 63 may be replaced with an electrically operatedsound-producing device or other signal means to provide a sensing signalindicating a defective electrical connection between the connector 23and the ground electrode 21. Both contacts 55 and 56 are connected tothe high-voltage line 64 to complete one line of the high-voltagecircuit. The high-voltage circuit is completed through the patient 11,the ground electrode 21, and line 20.

In use, the switch 52 is closed connecting the low-voltage source 46 tothe connector 23. With the relay 51 in its normal position, theswitching elements 57 and 58 are out of engagement with the contacts 55and 56. The element 58 engages the contact 54 closing the circuit to thelight 63. When the light 63 is on," there is nonelectrical contactbetween the connector 23 and the electrode 21 in that current does notflow via the ground electrode 21 between the contact plates 34 and 36.When the connector 23 is in proper electrical contact with the electrode21, the low-voltage circuit is completed through the plates 34 and 36via the electrical conductive skin 27 to energize the coil 49. Thismoves the switching elements 57 and 58 into engagement with the contacts55 and 56 thereby opening the circuit to the light 63 and closing thehigh-voltage circuit to the connector'23. Both contact plates 34 and 36are connected in the high-voltage circuit by virtue of the two switchingelements 57 and 58. The high-voltage circuit is completed through theactive electrode 19, the patient 11, and the cable 20. 7

Referring to FIGS. 5 and 6, there is shown the modified flat connector,indicated generally at 66, for connecting the line 22 to the disposableground plate electrode21. The connector 66 has a pair of identical clampcontact members 67 and 68 formed from conductive material, as sheetmetal. The contacts 67 and 68 are enclosed in and secured to flatidentical covers 69 and 71 of electrically insulative material, such asplastic and the like. The contact members 67 and 68 are identical instructure and are located in spaced side relation in the cover to form abipolar connector.

As shown in FIG. 6, clamp contact member 67 comprises a pair ofconductor members 72 and 73 having engaging transverse ribs 74 and 76secured together, as by spot welds, to form a one-piece clamp. Thecenter or body sections 77 and 78 of the members curve outwardly to forma transverse chamber 79. The forward portions of members 72 and 73 areflat contact plates 80 and 81 which are biased together by the curvedsections 77 and 78. Projected upwardly from the front and rear edges ofthe sections 80 and 81 are pairs of upright ears 82 and 83 securing theplates 80 and 81 to the covers 69 and 71. The forward or front edges ofthe plate contacts 80 and 81 have transverse outwardly directed flanges84 and 86 extended over the front side of cover walls 87 and 92,respectively. Flange 84 is located in a transverse groove 89 along thefront side of wall 87.

Located on opposite sides of the wall 87 are holes 88 for accommodatingthe cars 82. Wall 87 forms the bottom of the recess 90 in the cover 69which is closed with a strip closure 91 mounted on the cover flush withthe flat outer side of the cover 69. The member 72 is fastened to thewall 87 by turning the ears 82 over the top of the wall 87. Member 73 isattached to the wall 92 in a similar manner. The ears 83 project throughholes 93 in the cover on opposite sides of the wall 92 with the forwardflange 86 located in a transverse groove 94. The cover 69 has a recess96 for the turned over cars 83 which is closed with a strip closure 97mounted on the cover flush with the flat outer side of the cover 71.

With the members 72 and 73 secured to the walls 87 and 92, respectively,the transverse curved bodies 77 and 78 are in transverse engagementalong bearing or fulcrum lines 98 and 99 with transverse midportions ofthe covers 69 and 71. The lines 98 and 99 extend along the midsection ofthe covers rearwardly of the walls 87 and 92, so that upon movement ofthe covers 69 and 71 toward each other in the direction of the arrows100, the covers 69 and 71 will fulcrum along the fulcrum lines 98 and 99spreading the plate contacts 80 and 81, whereby the ground plateelectrode 21 may be inserted between the plate contacts 80 and 81. Thebiasing action of the curved sections 77 and 78 will hold the platecontacts 80 and 81 in flat surface engagement with opposite sides of theground plate electrode 21.

The peripheral edges of the covers 69 and 71 have inwardly directed sideand end flanges 101 and 102 located in a relative lapped relation sothat the covers can be moved toward each other and enclose theelectrical connections of the lines 43 and 44 to the clamp contactmembers 67 and 68, respectively.

As shown in FIG. 6, the front edges of the covers 69 and 71 haveforwardly projected and outwardly tapered nose portions 103 and 104which provide rearwardly converging guide surfaces leading to the platecontacts 80 and 81. The nose portions 103 and 104 extend transverselyparallel to the plate contacts 80 and 81 and are separated from eachother forming a mouth 94.

Referring to FIG. 7, there is shown a diagrammatic view of anelectrical-surgical unit, indicated generally at 106, connected to asplit ground plate electrode 107 with a cable 108 and a releasablebipolar clamp, indicated generally at 109. The cable 103 connects theclamp to a circuit testing unit 111 plugged into the electrical-surgicalunit 106. The electric circuit through the patient is completed by theuse of an active electrode coupled to a cable extended back to theelectricalsurgical unit 106, as illustrated in FIG. 1.

The ground plate electrode 107 is a rectangular-shaped one-piece sheetmember having a transverse flap or scored end 112 cooperating with theclamp 109 to prevent the accidental disengagement of the clamp from theground plate electrode. The corners 113 and 114 are curved or arcuate toeliminate sharp points and edges which may cut the patient or personnelin the operating theater.

As shown in FIG. 8, the ground plate electrode 107 has a flat andflexible base 114 which may be made of cardboard, paper, or similarflexible and electrically insulative material. Secured to the top of thebase 114 is a pair of spaced electrically conductive skins 116 and 117having flat and smooth surfaces. The skins 116 and 117 are located in aside-by-side relation and are separated from each other by alongitudinal space 118 extended down the longitudinal centerline of theground plate electrode 107. The skins 116 and 117 may be sheet materialor metal foil, as aluminum foil, bonded to the base 114. The skins havesmooth continuous top surfaces and outer peripheral edges 119 that areturned down into the adjacent edges of the base 114. The turned downedges 119 provide rounded edges around the entire ground plate, therebyeliminating any sharp edges which may injure the patient or operatingpersonnel. The base 114 is impregnated with a plastic material whichbonds the skins 116 and 117 to the top of the base. Other chemicals andmaterials can be used to treat and liquid-proof the base. The plasticmaterial increases the thermal characteristics of the ground plateelectrode 107 so that it can be placed in an autoclave forsterilization. In addition, the plastic material makes the entire groundplate electrode liquid-proof. The plastic material functions to maintaina continuous bond between the skins and the base so that the electrodemay be flexed and wrapped around a patient without separating the skinfrom the base or cracking the base. The back side of the base can beprinted with instruction and inventory code information with ink thatdoes not run or react with liquids or change with heat.

A specific example of the bipolar ground plate electrode 107, usable asa disposable electrode with an electrical-surgical unit,'is as follows.The base 114 is a cardboard sheet member having rectangular dimensionsof 8 by 13 inches. The base is electrically insulative cardboard about0.024-0022 inch thick. The skins 116 and 117 are 0.003 inch aluminumfoil bonded with plastic material to the top of the base. The base 114is entirely impregnated with plastic material. The longitudinal centerspace 118 extends the entire length of the electrode, including the flap112. The space has a width of as to inch. The rounded corners have aradius of 1 inch and the flap has a width of 9% inch. Other sizes andshapes of the ground plate electrode and the skins 116 and 117 areintended to be within the scope of the invention.

The bipolar clamp 109 has an elongated C member of split cylinder 121pivotally carrying a pair of converging levers 122 and 123. The leversextend through circumferentially spaced slots (not shown) in the back ofthe cylinder. Forward portions of the levers engage the transverse openedges of the split cylinder which biases these portions together. Thepart of the lever 122, projected forwardly from the cylinder 121, has afirst flat contact nose or plate 122A and a second contact nose or plate122B separated from the first contact plate with an electricallyinsulative strip 124. The strip 124 separates the lever 122 intoseparate electrical conductors. The lower lever 123 is also separatedinto two electrical conductors, each having rearwardly directed legs123A and 123B separated from each other with an electrically insulativestrip 125. The legs 123A and 1238 have flat upper surfaces that face theflat contact surfaces of the plates 122A and 1228.

Projected downwardly from the forward portion of the insulation strip124 is projection or pin 126 which extends through a hole 127 in theground plate electrode 107 and a hole 128 in the insulation strip 125 oflever 123. The hole 127 is located in the space 118 of the ground plateelectrode 107 adjacent the flap 112. Plates 122A and 1228 can each beprovided with a projection or pin adapted to extend through suitablespaced holes in the ground plate electrode. The use of two pins preventsrotation of the clamp relative to the ground plate electrode. The entireclamp 109, except for the contact plates 122A and 122B and correspondingsurfaces on the legs 123A and 1238, is coated with an electricallyinsulative material, as an electrically insulative plastic. This coatingprevents the grounding of the patient through the clamp and therebyavoids any contact burns.

The clamp 109 is releasably attached to the ground plate electrode 107by compressing the outer ends of the levers 122 and 123 to open themouth of the clamp by separating the contact plates 122A and 122B fromthe legs 123A and 1238. The ground plate electrode 107 with the flap 112in the folded position, as shown in FIG. 10, is inserted into the clamp.The middle of the clamp 109 is aligned with the space 118 by aligningthe projection 126 with the hole 127 and theground plate electrode 107.This positions the contact plate 122A in flat surface engagement withthe skin 116 and the contact plate 1223 in surface engagement with theskin 117. The projection 126, by extending through the hole 128 in thelower lever 123, prevents the accidental removal upon disengagement ofthe clamp 109 from the electrode 107. The only way the clamp 109 can beremoved from the electrode 107 is to depress and open the clamp toremove the projection 126 from the electrode 107. The purpose ofaligning the bipolar clamp 109 so that one electrical contact portion122A engages one skin 116 and the other contact plate 122B engages skin117, is to provide a structure and electrical circuit capable ofmonitoring the efficiency of the electrical conductivity between theground plate electrode 107 and the skin of a patient, as well as theelectrical connection between the clamp 109 and the ground plateelectrode 107 and the continuity of the cable 108. The circuit testingunit 111 functions to form these tests.

Referring to FIG. 11, there is shown the circuit testing unit 111separated from the electrical-surgical unit. The testing unit 111 has ahousing or casing 131 enclosing the electrical test circuit. Secured toone end of the housing is a male plug adapted to be inserted into acomplementary receptacle in the electrical-surgical unit to electricallyconnect the testing circuit with the electrical circuit of the unit 106.The opposite end of the housing 131 carries a female receptacle 133 forreceiving a male connector 134 secured to the end of the cable 108.

Exposed on the top of the housing 131 is an information scale or indicia136 which is indicative of the continuity of the circuit. The scale ismarked open, good, and short. Other indicia, as verbal, numerical, colorand the like. may be used to indicate the electrical condition of thecircuit. Associated with the scale is a movable pointer or finger 137which moves in response to the electrical circuit characteristics.Located below the scale is a movable switch button 138 operative toswitch the main ground circuit to the test circuit. The top of thehousing 131 also contains an adjustable screw or member 139 used tocalibrate the test circuit and compensate for the changes in thestrength of the test battery.

Referring to FIG. 12, there is shown the electrical circuit, indicatedgenerally at 141, between the ground plate electrode 107 and theterminals 144A and 1448 on the electricalsurgical unit 106. The circuitincludes the active electrode 142 connected with a line 143 to theterminal 144A. The ground plate electrode 107 is connected with a line146 to the terminal 144B. This line 146 provides a continuous ground forthe electrode 107. The line 146 is connected to one side of the lever122. A second line 147 is connected to the opposite side of the lever122 whereby both electrical conductive portions of the lever 122 areconnected to the electrical-surgical generator. Interposed in line 147is a switch, indicated generally at 148. The switch 148 has a first pairof contacts 151 and 152 connected to the line 147. The manually operatedbutton 138 is connected to a movable bar or contact 156 which isnormally engageable with the contacts 151 and 152 to complete thecircuit through line 147. A spring 149 continuously biases the switch148 to theclosed position electrically connecting the contacts 151 and152. As soon as the pressure or force is relieved from the switch button138, the switch 148 will automatically return to the closed portion.

Switch 148 has a second pair of contacts 153 and 154 adapted to beengaged by the movable contact 156 upon depression of the button 138.Contact 153 is located in a line 157 connected to the line 147 betweenthe contact 151 and the clamp 109. A battery 158, as a low-power 9-voltDC battery, is connected to the line 146 with a line 159. The battery158 is also connected to a variable resistance 161 which is adjustablewith the screw 139 to calibrate the electrical output of the battery. Aline 162 connects the variable resistance 161 to a galvanometer orsimilar instrument for measuring the electrical current in a circuit.The meter 163 is connected with a line 164 to the switch contact 154.Upon depression of the button 139, the bar 156 engages the contacts 153and 154, .as shown in broken lines, to complete the test circuit to themeter 163 and the skins 116 and 117. The test circuit 141 functions totest the continuity of the lines or cable 108 between the unit 111 andthe clamp 109, the electrical connection between the clamp contactplates 122A and 1228 and the corresponding electrical conductive skins116 and 117, and the electrical surface connection or resistivitybetween the skin portion ofa patient, indicated at 166 in FIGS. 7 and12, in surface engagement with both of the skins 116 and 117. The meter163 will indicate a lack of effective electrical contact between thepatients skin and the electrical skin conductors 116 and 117. When theindicator or pointer 137 is in the open position, as shown in FIG. 11,the contact between the patient and the ground plate is insufficient tohave an effective operation of the active electrode. When the pointer137 is in the short range, the circuit is grounded. This may indicate animproper positioning of the clamp on the ground plate electrode so thata single contact plate, as plate 122A, engages both electricallyconductive skins 116 and 117. An open circuit may indicate a break inthe cable or electrical connection between the cable and the clamp, oran insufficient electrical connection between the clamp and the groundplate electrode.

When the test circuit indicates an open or insufficient elec tricalconnection between the patient 166 and the ground plate electrode, itmay be necessary to reposition the electrode on the patient or addelectrically conductive jelly, or other conductive material, to increasethe electrical connection between the patient's skin and the groundplate electrode. It may be necessary to reposition the clamp on theelectrode to insure a surface contact between the contact plate 122A andskin 116 and contact plate 122B and skin 117.

Referring to FIG. 13, there is shown a ground plate electrode 167 havinga generally rectangular shape. Electrode 167 has a flexible base 168which can be made of cardboard, paper, wood, and similar material. Thebase is substantially flat, flexible, and electrically insulative.Attached to the top of the base 168 is a pair of substantially identicalelectrical conductive skins 169 and 171. The skins are spaced from eachother along the longitudinal centerline of the base with a uniformlongitudinal space 172. The skins 169 and 171 are electricallyconductive sheet members having flat continuous and smooth top surfaces.The skins 169 and 171 may be made of sheet metal, metal foil, and likeelectrically conductive material, as aluminum foil. The skins can bebonded or secured to the top of the base 168 with an adhesive or plasticmaterial embedded in the base 168. Other chemicals, bonding and adhesivematerials can be used to treat and liquid-proof the base, as well asbond the skins 169 and 171 to the base 168. The treatment of the baseincreases its thermal characteristics, as well as its resistance tochemical action and liquids, as water, blood, and like. The peripheraledges of the ground plate are rounded to eliminate any sharp edges whichmay injure a patient or operating personnel, as shown in FIG. 8 of thedrawing.

One end of the ground plate electrode has a flap or flange 173 extendedacross the end of the electrode and defined with a crease or fold line174. The crease 174 permits the easy and convenient folding of the flapprior to insertion into the clamp. The corners 176 and 177 of theopposite end of the electrode are rounded or curved to eliminate anysharp points or edges. lnwardly of the flap 173 in the midsection of thebase 168 is a clamp locator hole 178. The electrode 167 can be providedwith two other holes 178A and 1788 for the purpose of locating andholding the clamp on'the electrode.

The clamp, indicated generally at 179, is a bipolar connector operativeto make separate surface electrical connections with the skins 169 and171. As shown in FIG. 14, clamp 179 is connected to a two-line cable 180leading to the circuit test unit and electrical-surgical machine. Asshownin FIG. 15, the clamp 179 comprises a pair of identical generallyflat lever members 180 and 181 which are pivotally connected together ina manner so that the front sections thereof are biased together. Levermembers 180 and 181 have front relatively flat portions 182 and 183 andupwardly and outwardly directed rear portions 184 and 186, respectively.The rear portions 184 and 186 diverge from each other from a transversepivot rod 187. The sides of the lever members have inwardly directedside flanges 185. Each lever member 180 and 181, including the ears,rib, and side flanges, is a one-piece nonelectrical conductive plasticmember resistant to heat and liquids, as blood and water. Materialsother than plastic can be used to make the lever members. The obtuseangular shape of the lever members 180 and 181 enable the clamp to openwide for cleaning and attachment to the ground plate electrode.

As shown in FIG. 16, each lever member has a plurality of laterallyspaced downwardly projected ears 188 and 189 which have end portionsthat overlap each other to accommodate the transverse pivot rod 187/Rod187 is made of electrical insulative material. Rod 187 can be separatedinto two parts with the center portions of the parts spaced from eachother. The forward portions 182 and 183 of the lever members are biasedtoward each other by a pair of torsion coil springs 192 and 193telescoped over opposite end portions of the rod 187. Each spring has apair of ends 192A, 192B, and 193A, 1935, which extend outwardly from thepivot rod 187 and engage the inside portions of the electricalconductors A and 196A and 194A and 194B mounted on the lever members andthereby continuously bias the front portions 182 and 183 into engagementwith each other. The springs 192 and 193 provide electrical connectionsbetween adjacent upper and lower flat conductors 195A, 196A and 194A,1948. Lever portions 184 and 186 have short projections or stubs 184Aand 186A projected inwardly to retain conductors 195A and 196A inassembled relation with the lever members. Additional projections areused to hold conductors 194A and 1948. Cable 180 has a first line 180Aconnected to conductor 194A and a second line 1808 connected toconductor 195A.

Returning to FIG. 14, the clamp 179 has a pair of spaced electricalcontact plates 194 and 195 in surface engagement with the electricallyconductive skins 169 and 171. Plate 194 is only in surface engagementwith the skin 169 and plate 195 is only in surface engagement with theskin 171. The adjacent ends of plates 194 and 195 are spaced from eachother a distance greater than the space 172 so that a single contactplate does not engage both skins 169 and 171. Preferably, this distanceis approximately one inch. As shown in FIG. 17, the

contact plate 195 is clamped onto a flat transverse rib 197. The rib197, extended across the inside of the front portion 182, has a fronttransverse groove 198 and a rear transverse step 199. Plate 195 has aturned front terminating in a transverse edge 1953 located in the groove198. The rear portion of the plate 195 is offset, located adjacent step199, and joined with conductor 195A. Plates 194 and 196 are attached totheir ribs in the same manner. The rib 197 extends downwardly orinwardly from the inside face of the lever member 180 to form a space orpocket 201 to accommodate the flap or flange 173. The lever member 181has a similar rib for carrying the contact plate 195 so that the pocket201 has a large transverse space between the front portions 182 and 183of the lever members.

Referring to FIG. 18, there is shown the lever member 180 having adownwardly directed projection or pin 202 integral with the midportionof the rib 197. The projection 202 extends through the hole 178 in theground plate electrode and into a hole 203 in the lever member 181. Theprojection 202 provides a positive coupling of the clamp 179 to theground plate electrode 167. The clamp cannot be accidentally removedwithout spreading the lever members 180 and 181. By locating the hole178 in the base 168 within space 172, the electrical contact plates 194and 195 are aligned with their respective electrically conductive skins169 and 171. The clamp can have a pair of spaced pins or projectionsadapted to extend through holes 178A and 1788 in the electrode 167.These projections can be secured to the plates 194 and 195 or extendthrough holes in these plates. The use of two spaced projectionsprevents rotation of the clamp relative to the electrode, as well asaccidental removal of the clamp from the electrode.

FIG. 19 shows the forward portion ofa modified clamp, indicatedgenerally at 179A, The clamp 179A is identical with the clamp 179,except for the elimination of the projection or pin 202. The electrode167 is retained in the clamp 179A by folding the flange 173 along thefold line 174. in this manner, the forward edge of the flange willcooperate with the rib 197A to prevent the accidental disengagement ofthe electrode 167 from the clamp. The folded portion of the electrode islocated in the transverse space 201A between the lever portions 182A and183A.

While there have been shown and described preferred embodiments oftheground plate electrode, the clamp releasably attached to the groundplate electrode, and the circuit-testing apparatus for monitoring theelectrical characteristics of the ground plate electrode and connectionsthereto, including the resistivity between the patient and ground plateelectrode, it is to be understood that various changes, substitutions,and deletions may be made by those skilled in the art without departingfrom the spirit ofthe invention.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. In combination: an electrode having a base and electricallyconductive skin means secured to at least one side of the base. clampmeans releasably attached to a portion of the electrode, said clampmeans having at least two separated electrical contact members, means tohold the contact members in surface engagement with separate portions ofthe electrically conductive skin means, and means cooperating with theelectrode to prevent accidental separation of the clamp means from theelectrode, and electric circuit means connected to the contact membersof the clamp means for testing the electrical connections between theelectrically conductive skin means of the electrode and the separatecontact members of the clamp means, said circuit means adapted to beconnected to a source of electric power to provide electric energy tothe circuit means to test said electrical connections.

2. The combination of claim 1 wherein: the means cooperating with theelectrode to prevent accidental separation of the clamp means from theelectrode comprise means on said clamp means engageable with a turnedflange of said electrode.

3. The combination of claim 1 wherein: the circuit means comprises alow-voltage circuit connected to and completed through said contactmembers and electrically conductive skin means, a relay having a coiland switch contacts, said coil located in said low-voltage circuit, ahigh-voltage circuit containing said switch contacts and connected tothe contact members of the clamp means whereby when the low-voltagecircuit is completed in the coil, it is energized closing the switchcontacts to complete the high-voltage circuit to the electrode.

4. The combination of claim 3 wherein: the low-voltage circuit includessignal means providing a recognizable indication when the high-voltagecircuit is open.

5. The combination of claim 1 wherein: the circuit means has a firstcircuit connected to the separate contact members, a second circuitconnected to at least one of the contact members, and means operable oncompletion of the first circuit to close the second circuit.

6. The combination of claim 5 wherein: the first circuit is a lowvoltagecircuit and the second circuit is a high-voltage circuit.

7. The combination of claim 5 wherein: the means operable on completionof the first circuit to close the second circuit includes relay meanshaving a control element in the first circuit and switches in the secondcircuit operable by the control element so that on completion of thefirst circuit the control element will close the switches therebyclosing the second circuit.

8. The combination of claim 1 wherein: said electrode has hole means andthe means cooperating with the electrode to prevent accidentalseparation of the clamp means from the electrode comprise projectionmeans extended through said holes means.

9. The combination of claim 1 wherein: the means cooperating with theelectrode to prevent accidental separation of the clamp means from theelectrode comprise at least one projection extended through a hole inthe electrode and cooperating with the contact members to hold the clampmeans in assembled relation with the electrode.

10. The combination of claim 1 wherein: the clamp means has a covermeans located over the contact members, said contact members secured toa portion of the cover.

11. In combination: an electrode having a base, a first electricallyconductive skin and a second electrically conductive skin spaced fromthe first skin, said first and second skins secured to said base andadapted to contact a body, clamp means releasably attached to a portionof the electrode, said clamp means having first electrical contact meansengageable with the first skin and second electrical contact meansengageable with the second skin, means holding the first and secondcontact means in engagement with said skins. and means cooperating withthe electrode to prevent accidental separation of the clamp means fromthe electrode, and electric circuit means connected to the first andsecond contact means of the clamp means for testing the electricalconnections between the electrically conductive skin means of theelectrode and the separate contact means of the clamp means and formonitoring the electrical conductivity of the electrical connectionsbetween a body and the portions of the first and second skins inengagement with the body, said circuit means adapted to be connected toa source of electric power to provide electric energy to the circuitmeans to test said electrical connections.

12. The combination of claim 11 wherein: the means cooperating with theelectrode to prevent accidental separation of the clamp means from theelectrode comprise means on said clamp means engageable with a turnedflange of said electrode.

13. The combination of claim 11 wherein: said circuit means includes anelectric power source, a meter connected to the power source, and aswitch operable to couple the meter and power source in series with thefirst skin and second skin.

14. The combination of claim 13 wherein: said power source is a batteryand said test circuit includes a variable re sistance operable tocalibrate the power output of the battery,

15. The combination of claim 1 1 wherein: the circuit means includes aline that continuously connects at least one conductive skin to groundand a test circuit for monitoring the conductivity of the electricalconnection between the patient and the portions of the first and secondskins in engagement with the patient.

16. The combination of claim 11 wherein: said clamp means has a firstlever with a forward portion connected to the first contact means andthe second contact means, a second lever, means pivotally connecting thefirst lever with the second lever, and biasing means urging forwardportions of the first lever and second lever toward each other.

17. The combination of claim 16 wherein: the first lever has a generallyflat forward portion and an upwardly and outwardly directed rearportion.

18. The combination of claim 11 wherein: the means cooperating with theelectrode to prevent accidental separation of the clamp means from theelectrode comprise at least one projection extended through a hole inthe electrode when the clamp is attached to the electrode.

19. The combination of claim 18 wherein: the clamp means has two spacedprojections extended through spaced holes in the electrode when theclamp is attached to the electrode.

20. The combination of claim 11 wherein: said circuit means includes anindicator means operable to provide a readable signal in response to theelectrical connections between the electrical contact means and thefirst and second skins and the electrical connection between the bodyand the first and second skins.

21. The combination of claim 20 wherein: said indicator means is anelectrical meter.

22. The combination of claim 11 wherein: the means cooperating with theelectrode to prevent accidental separation of the clamp means from theelectrode comprises at least one projection extended through a hole inthe electrode between the first skin and the second skin when the clampmeans is attached to the electrode, said projection being locatedbetween the first contact means and second contact means, whereby theprojection aligns each contact means with a skin.

23. The combination of claim 11 wherein: the first skinand the secondskin are longitudinally aligned relative to each other and secured toone side of the base, said skins being separated from each other alongthe longitudinal center of the electrode.

1. In combination: an electrode having a base and electricallyconductive skin means secured to at least one side of the base, clampmeans releasably attached to a portion of the electrode, said clampmeans having at least two separated electrical contact members, means tohold the contact members in surface engagement with separate portions ofthe electrically conductive skin means, and means cooperating with theelectrode to prevent accidental separation of the clamp means from theelectrode, and electric circuit means connected to the contact membersof the clamp means for testing the electrical connections between theelectrically conductive skin means of the electrode and the separatecontact members of the clamp means, said circuit means adapted to beconnected to a source of electric power to provide electric energy tothe circuit means to test said electrical connections.
 2. Thecombination of claim 1 wherein: the means cooperating with the electrodeto prevent accidental separation of the clamp means from the electrodecomprise means on said clamp means engageable with a turned flange ofsaid electrode.
 3. The combination of claim 1 wherein: the circuit meanscomprises a low-voltage circuit connected to and completed thRough saidcontact members and electrically conductive skin means, a relay having acoil and switch contacts, said coil located in said low-voltage circuit,a high-voltage circuit containing said switch contacts and connected tothe contact members of the clamp means whereby when the low-voltagecircuit is completed in the coil, it is energized closing the switchcontacts to complete the high-voltage circuit to the electrode.
 4. Thecombination of claim 3 wherein: the low-voltage circuit includes signalmeans providing a recognizable indication when the high-voltage circuitis open.
 5. The combination of claim 1 wherein: the circuit means has afirst circuit connected to the separate contact members, a secondcircuit connected to at least one of the contact members, and meansoperable on completion of the first circuit to close the second circuit.6. The combination of claim 5 wherein: the first circuit is alow-voltage circuit and the second circuit is a high-voltage circuit. 7.The combination of claim 5 wherein: the means operable on completion ofthe first circuit to close the second circuit includes relay meanshaving a control element in the first circuit and switches in the secondcircuit operable by the control element so that on completion of thefirst circuit the control element will close the switches therebyclosing the second circuit.
 8. The combination of claim 1 wherein: saidelectrode has hole means and the means cooperating with the electrode toprevent accidental separation of the clamp means from the electrodecomprise projection means extended through said holes means.
 9. Thecombination of claim 1 wherein: the means cooperating with the electrodeto prevent accidental separation of the clamp means from the electrodecomprise at least one projection extended through a hole in theelectrode and cooperating with the contact members to hold the clampmeans in assembled relation with the electrode.
 10. The combination ofclaim 1 wherein: the clamp means has a cover means located over thecontact members, said contact members secured to a portion of the cover.11. In combination: an electrode having a base, a first electricallyconductive skin and a second electrically conductive skin spaced fromthe first skin, said first and second skins secured to said base andadapted to contact a body, clamp means releasably attached to a portionof the electrode, said clamp means having first electrical contact meansengageable with the first skin and second electrical contact meansengageable with the second skin, means holding the first and secondcontact means in engagement with said skins, and means cooperating withthe electrode to prevent accidental separation of the clamp means fromthe electrode, and electric circuit means connected to the first andsecond contact means of the clamp means for testing the electricalconnections between the electrically conductive skin means of theelectrode and the separate contact means of the clamp means and formonitoring the electrical conductivity of the electrical connectionsbetween a body and the portions of the first and second skins inengagement with the body, said circuit means adapted to be connected toa source of electric power to provide electric energy to the circuitmeans to test said electrical connections.
 12. The combination of claim11 wherein: the means cooperating with the electrode to preventaccidental separation of the clamp means from the electrode comprisemeans on said clamp means engageable with a turned flange of saidelectrode.
 13. The combination of claim 11 wherein: said circuit meansincludes an electric power source, a meter connected to the powersource, and a switch operable to couple the meter and power source inseries with the first skin and second skin.
 14. The combination of claim13 wherein: said power source is a battery and said test circuitincludes a variable resistance operable to calibrate the power output ofthe battery.
 15. The combination of Claim 11 wherein: the circuit meansincludes a line that continuously connects at least one conductive skinto ground and a test circuit for monitoring the conductivity of theelectrical connection between the patient and the portions of the firstand second skins in engagement with the patient.
 16. The combination ofclaim 11 wherein: said clamp means has a first lever with a forwardportion connected to the first contact means and the second contactmeans, a second lever, means pivotally connecting the first lever withthe second lever, and biasing means urging forward portions of the firstlever and second lever toward each other.
 17. The combination of claim16 wherein: the first lever has a generally flat forward portion and anupwardly and outwardly directed rear portion.
 18. The combination ofclaim 11 wherein: the means cooperating with the electrode to preventaccidental separation of the clamp means from the electrode comprise atleast one projection extended through a hole in the electrode when theclamp is attached to the electrode.
 19. The combination of claim 18wherein: the clamp means has two spaced projections extended throughspaced holes in the electrode when the clamp is attached to theelectrode.
 20. The combination of claim 11 wherein: said circuit meansincludes an indicator means operable to provide a readable signal inresponse to the electrical connections between the electrical contactmeans and the first and second skins and the electrical connectionbetween the body and the first and second skins.
 21. The combination ofclaim 20 wherein: said indicator means is an electrical meter.
 22. Thecombination of claim 11 wherein: the means cooperating with theelectrode to prevent accidental separation of the clamp means from theelectrode comprises at least one projection extended through a hole inthe electrode between the first skin and the second skin when the clampmeans is attached to the electrode, said projection being locatedbetween the first contact means and second contact means, whereby theprojection aligns each contact means with a skin.
 23. The combination ofclaim 11 wherein: the first skin and the second skin are longitudinallyaligned relative to each other and secured to one side of the base, saidskins being separated from each other along the longitudinal center ofthe electrode.